<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
    <style>
      #happy {
        width: 100px;
        height: 50px;
        background-color: pink;
      }
    </style>
  </head>
  <body>
    <div id="happy">happy!happy!happy!</div>
  </body>
  <script>
    const happy = document.getElementById("happy");
    happy.onclick = function () {
      alert("happy!happy!happy!");
    };
  </script>
</html>
